Dissertations / Theses on the topic 'Standing waves'
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Santos, Alisson Darós. "Estabilidade de Standing waves." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/5903.
Full textFinanciadora de Estudos e Projetos
This work is concerned with the orbital stability of special solutions called "standing waves" for Hamiltonian systems in a real and invariant Hilbert space under the action of a specific group of isometries in such space. The stability investigated is orbital in the usual sense for a dynamical system and is with respect to perturbations of the initial condition. Initially we approach the problem in an abstract manner and then we show an application of the discussed method.
Estudamos, neste trabalho, a estabilidade orbital de soluções especiais do tipo "standing wave" para sistemas hamiltonianos em um espaço de Hilbert real e invariante sob a ação de específico grupo de isometrias em tal espaço. A estabilidade investigada para este perfil de soluções considera perturbações ocorrentes na condição inicial pré-fixada. Inicialmente, abordamos a técnica abstratamente para a obtenção da estabilidade orbital e, posteriormente, apresentamos uma aplicação do método discutido.
Mercer, Geoffry Norman. "On standing waves and models of shear dispersion /." Title page, contents and summary only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phm5541.pdf.
Full textDolven, Eric T. "Seaquake waves - standing wave dynamics with Faraday excitation and radiative loss /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/6785.
Full textCragg, George E. (George Edwin) 1972. "Laterial resolution enhancement with standing evanescent waves." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/89264.
Full textDostal, Jack Alan. "An investigation into student understanding of longitudinal standing waves." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/dostal/DostalJ1208.pdf.
Full textSegal, Joseph. "STANDING WAVES OF SPATIALLY DISCRETE FITZHUGH-NAGUMO EQUATIONS." Master's thesis, University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3511.
Full textM.S.
Department of Mathematics
Sciences
Mathematical Science MS
Ali-Kianifar. "Detection of standing waves in pump/pipework systems." Thesis, University of Strathclyde, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314587.
Full textHutchinson, John Michael. "Particle and bubble filtration using ultrasonic standing waves." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46355.
Full textKraucunas, Ian. "The influence of hemispheric asymmetry and realistic basic states on tropical stationary waves in a shallow water model /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/10030.
Full textDostal, Jack Alan. "An investigation into student understanding of longitudinal standing waves." Diss., Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/dostal/DostalJ0509.pdf.
Full textSmith, M. R. "The separation of particle suspensions using ultrasonic standing waves." Thesis, Cranfield University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317142.
Full textFukuizumi, Reika. "Stability and instability of standing waves for nonlinear Schrödinger equations /." Sendai : Tohoku Univ, 2003. http://www.gbv.de/dms/goettingen/383854059.pdf.
Full textChen, Chih-Lyeu. "Experimental investigation of energy dissipation in finite-amplitude standing waves." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/30949.
Full textThermoacoustic engines are designed to perform optimally at one frequency. However, the thermoacoustic prime movers have been shown to generate highly nonlinear waveforms, in which a significant amount of the acoustic energy appears in higher harmonics. This condition reduces the overall efficiency of the engine. The harmonics can be suppressed. But does the suppression mean that more energy remains in the fundamental frequency? This question is the topic of this thesis. Finite-amplitude standing waves were generated in a standing wave tube. The steady state input acoustic power was compared to the steady state dissipated acoustic power for two configurations - an empty tube and an obstructed tube - over a wide range of input powers. The waveforms in the empty tube were rich in harmonics, whereas the obstruction suppressed the harmonics significantly. The results of the measurements indicate that suppression of the harmonics also suppresses the transfer of energy from the fundamental.
Mathers, Philip. "The effect of acoustic standing waves on vacuum coating technology." Thesis, Cranfield University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263535.
Full textLandry, Blake Jude. "Bathymetric evolution of sand bed forms under partially standing waves." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29380.
Full textIncludes bibliographical references (v. 2, p. 345-347).
Experiments were conducted in a large wave flume where the interaction between water waves and a movable sand bed were investigated. Monochromatic and poly- chromatic waves of specified amplitudes and period were generated under cases of weak (R=0.2) and/or strong (R=0.9) reflections. Experiments included one of two mean grain sand sizes (0.2mm and O.mm) to examine the effects of different sediment transport modes (bed load and suspended load), on the over all evolution of the sand bed. Throughout the experiments, conductivity probes measured the surface wave envelope, charged-coupled device (CCD) cameras recorded small scale (ripple) formations and migrations, while a digital camera was employed to capture large scale variations (bars) and ripples over the entire sand bed. A final experiment was conducted using a mixture of the two uniform grain size to observe sediment sorting within the sand bed. Numerous sieve analysis and measurements of the active sorting sand depth were performed on sediment samples from various positions along the flume to quantitatively study the phenomena of sediment sorting.
by Blake Jude Landry.
S.M.
Kikuchi, Hiroaki. "Existence and stability of standing waves for Schrodinger-Poisson-Slater equation." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/136854.
Full textCorrigan, Timothy J. "A preliminary investigation of high amplitude standing waves with laser Doppler anemometry." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA276463.
Full textO'Hare, Timothy James. "Sand bar evolution beneath partially-standing waves : laboratory experiments and model simulations." Thesis, Bangor University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305141.
Full textChung, Euiheon. "Super-resolution wide-field optical microscopy by use of Evanescent standing waves." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38594.
Full textVita.
Includes bibliographical references.
The development of high resolution, high speed imaging techniques allows the study of dynamical processes in biological systems. Optical fluorescence microscopy is an essential tool for investigations in many disciplines in biology and medicine with molecular specificity. The resolution of optical far-field microscopy has been limited by the wave nature of light. In this thesis, a microscopy technique, standing wave total internal reflection fluorescence (SW-TIRF), has been developed with resolution beyond the classical diffraction limit. The SW-TIRF approach modifies the point-spread function to effectively decrease the excitation wavelength by utilizing an evanescent standing wave, carrying high spatial frequency information near the interface between the specimen and a high refractive index substrate. Evanescent standing wave illumination is used to generate a sinusoidal, high-spatial frequency, fringe pattern on the specimen providing lateral resolution enhancement. Furthermore, the less than 100 nm penetration depth of the evanescent field from the substrate ensures a thin excitation region resulting in low background fluorescence. The first experimental realization of SW-TIRF in an objective-launched geometry demonstrates the potential for super-resolution imaging at high speed in wide-field microscopy.
(cont.) The super-resolution has been realized with the effective point-spread function providing better than a fifth of the emission wavelength or approximately 100 nm, which is better than twice that of conventional microscopy. In addition, imaging biological specimens with SW-TIRF demonstrated the performance revealing the fine actin cytoskeleton structures of fibroblasts. On the other hand, the surface plasmons induced by evanescent fields at a specific angle can generate an enhanced electric field which can effectively excite fluorophores near a metal coated surface. We observed a unique doughnut-shaped point-spread function of surface plasmon coupled emission and explained it with theoretical modeling using vector field theory. The combination of surface plasmon resonance fluorescence imaging and SW-TIRF resulted in a novel high-resolution microscopy, the standing wave surface plasmon resonance fluorescence (SW-SPRF) microscopy. These findings may allow super-resolution imaging with even higher sensitivity and signal-to-noise ratio at high imaging speed.
by Euiheon Chung.
Ph.D.
Yamazaki, Yohei. "Stability of line standing waves near the bifurcation point for nonlinear Schrodinger equations." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199077.
Full textLoskutova, Ksenia. "Cell viability of K562 cells in pressure anti-nodes of ultrasonic standing-waves." Thesis, KTH, Tillämpad fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233517.
Full textGeyer-Schulz, Andreas [Verfasser], and R. [Akademischer Betreuer] Schnaubelt. "Maxwell–Schrödinger System: Well-Posedness and Standing Waves / Andreas Geyer-Schulz ; Betreuer: R. Schnaubelt." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1202076874/34.
Full textWang, Jin. "X-ray standing waves and their use in characterizing biologically relevant thin film systems /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487849696965678.
Full textJonsson, Ulf G. "Detecting Inclusions in a Silicone Rubber Phantom Using Standing Lamb Waves and Multiple Frequency Footprints." Doctoral thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-88220.
Full textDenna avhandling berör frågan: är det möjligt, med en piezoelektrisk sensor/vibrator, att detektera ett hårt objekt inneslutet i en fantom av silikongummi? Frågan närmades utan begränsningar och uppgiften delades upp i tre tydliga delar: karaktäriseringen av den piezoelektriska sensorn/vibratorn (paper I), skapa en modell av det viskoelastiska uppförandet hos ett vävnadsliknande material (fantom) som står i kontakt med sensorn-/vibratorn (paper II) och att detektera förekomsten av ett hårt objekt inneslutet i fantomen (paper III). En finit element modell (FEM) skapades för att beräkna vibrationerna hos sensorn/vibratorn och fantomen. För att minimera beräkningstiden och maximera modellens förmåga att återge vibrationer på ett korrekt sätt, så skapades ett tvådimensionellt modellsystem bestående av en cylindrisk piezoelektrisk sensor/vibrator i kontakt med en cylindrisk fantom av silikongummi. Sensorn/vibratorn skickar radiella elastiska vågor in i fantomen. Den piezoelektriska sensorn/vibratorn karakteriserades med hjälp av en procedur som anpassar parametervärden med hjälp av övertoner. Proceduren möjliggör en justering av parametervärdena så att uppmätta och beräknade impedansspektra överensstämmer. En 'fractional derivative' modell av de viskoelastiska egenskaperna hos silikongummit skapades. De hyperelastiska egenskaperna vid första radiella resonansen blev kompenserade med hjälp av en sigmoidformad funktion. Den komplexa viskoelastiska modulen bestämdes för höga frekvenser med hjälp av transitioner hos stående Lambvågor i fantomen. Närvaron av ett hårt ringformat objekt i fantomen detekterades med hjälp av förändringar i mönstret hos de stående Lambvågorna. Justeringen av de piezoelektriska parametrarna hos elementet PZT5A1 gav som mest en skillnad på 0.54% mellan uppmätta och beräknade impedansspektra. Medelvärdet hos tre prov av silikongummit Silgel 612 av den komplexa elastiska modulen uppmättes till (0.97 + 0.009i) GPa vid 100 kHz och (0.97 + 0.005i) GPa vid 250 kHz. Närvaron av ett hårt objekt, gjort av polyaramid (PA6GPE), detekterades i fantomen med hjälp av multifrekvensiella fotavtryck.
Kariapper, Mohamed Sirajudeen. "X-ray standing wave studies of surface adsorption structures." Thesis, University of Warwick, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365232.
Full textWu, Meiyi. "Development of the x-ray standing waves methodology to probe the interfaces of periodic multilayers." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS175/document.
Full textThe interfacial information of periodic multilayers can be crucial for the development of reflecting mirrors which operate in the X-ray and extreme ultraviolet (X-EUV) ranges. Such information may contain the interdiffusion and chemical process at the interfaces of the layers. The idea of this thesis is to apply the X-ray standing wave technique to the characterization of materials, mainly but not limited to the periodic multilayers. X-ray standing wave technique enables to enhance the excitation (photoemission, fluorescence etc.) of specific locations within a periodic stack. The nature of such advantage is the interference of two coherent X-ray beams. One may compare the X-ray standing waves with the mechanical standing waves. The constructive interference at the anti-nodal plane amplifies the electric field; while the destructive interference at the nodal plane minimizes the electric field. In this way, the experimental spectra obtained under standing wave field will be mostly the material located on the anti-nodal plane. Combined with other techniques such as X-ray emission spectroscopy and X-ray photoelectron spectroscopy, a depth-selective information with a sub-nanoscale sensitivity can be obtained
Ahmad, Saad. "Modeling the Discharge Loading of Radio Frequency Excited CO2 Slab lasers." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-theses/1081.
Full textEdvardsson, Elisabet. "Quasicrystals : Classification, diffraction and surface studies." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-36299.
Full textGollwitzer, Jakob [Verfasser]. "Magnon-Photon Interactions: From X-ray Mapping of Standing Spin Waves to Fano Interference in Cavity Electromagnonics / Jakob Gollwitzer." München : Verlag Dr. Hut, 2020. http://d-nb.info/1219476552/34.
Full textArlinghaus, Stephan [Verfasser], Martin [Akademischer Betreuer] Holthaus, and Andreas [Akademischer Betreuer] Engel. "Controlling Ultracold Atoms with Modulated Standing Light Waves: Present Status and Future Perspectives / Stephan Arlinghaus. Betreuer: Martin Holthaus ; Andreas Engel." Oldenburg : BIS der Universität Oldenburg, 2012. http://d-nb.info/1075317053/34.
Full textSevero, Uberlandio Batista. "Estudo de uma classe de equações de Schrodinger quase-lineares." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307293.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: Neste trabalho, estudamos questões relacionadas à existência, multiplicidade e comportamento de concentração de soluções do tipo onda estacionária, para uma classe de equações de Schrödinger quase-lineares, as quais modelam fenômenos físicos, por exemplo, na F³sica de Plasmas. Na obtenção de nossos resultados, usamos métodos variacionais, tais como, teoremas do tipo mini-max, bem como, teoria de regularidade de equações elípticas de segunda ordem
Abstract: In this work, we study questions related to existence, multiplicity and concentration behavior of standing waves, for a class of quasilinear Schrödinger equations, arising, for example, in Plasma Physics. To obtain our results, we use variational methods, such as, minimax theorems and also regularity theory of elliptic equations of second order
Doutorado
Analise
Doutor em Matemática
Ye, Fan. "Surface plasmon polaritons along metal surfaces with novel structures." Thesis, Boston College, 2014. http://hdl.handle.net/2345/bc-ir:103747.
Full textSurface plasmon polaritons (SPPs) are hybridized quasiparticles of photons and electron density waves. They are confined to propagate along metal-dielectric interfaces, and decay exponentially along the direction perpendicular to the interfaces. In the past two decades, SPPs have drawn intensive attention and undergone rapid development due to their potential for application in a vast range of fields, including but not limited to subwavelength imaging, biochemical/biomedical sensing, enhanced light trapping for solar cells, and plasmonic logic gates. These applications utilize the following intrinsic properties of SPPs: (1) the wavelength of SPPs is shorter (and can be much shorter) than that of free photons with the same frequency; (2) the local electric field intensity associated with SPPs can be orders of magnitude larger than that of free photons; and (3) SPPs are bound to metal surfaces, and are thus easily modulated by the geometry of those surfaces. Here, we present studies on SPPs along metal surfaces with novel structures, including the following: (1) SPP standing waves formed along circular metal surfaces that lead to a "plasmonic halo" effect; (2) directional reflectionless conversion between free photons and SPPs in asymmetric metal-insulator-metal arrays; and (3) broadband absorbance enhancement of embedded metallic nanopatterns in a photovoltaic absorber layer. These works may prove useful for new schemes for SPP generation, plasmon-photon modulation, ultrasensitive dielectric/bio sensing, and high efficiency thin film solar cells
Thesis (PhD) — Boston College, 2014
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
Vozárová, Juliana. "Stanovení akustické pohltivosti materiálu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-432822.
Full textBen, Jabrallah Soumaya. "Electrolytes aux interfaces : accès aux premiers nanomètres par la technique des ondes stationnaires." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066709/document.
Full textThe distribution of ions and charges at solid-water interfaces is of key importance in a number of phenomena and processes. In particular the development of microfluidics has strengthened the need for understanding and controlling ion distributions in the electric double layer. Indeed, phenomena occurring within the diffuse Gouy-Chapman layer become dominant in determining flow properties as channel size become on the same order of magnitude of the Debye length. In this thesis, we used the technique of X-ray standing waves to determine the distribution of interfacial ions. We have developed cells with thicknesses of a few hundred nanometers or less, precisely measured by X-ray reflectivity. The liquid film is confined between the multilayer which create the standing wave and a polymer film. The ion fluorescence allows to determine the interfacial distribution with a spatial resolution of a few Angstroms. This work was carried out for solutions containing different mixtures of monovalent ions (chloride, potassium, cesium and iodine) at several concentrations.In the second part of this work, we present the results for lanthanide chlorides. These studies have allowed us to determine the composition of the Stern layer and the distribution of ions in this layer for all pairs La3+/Ce3+, La3+/Eu3+, La3+/Gd3+, Ce3+/Eu3+, Ce3+/Gd3+ et Eu3+/Gd3+. We could then classify these ions and discuss the series
Souza, Arlan Lucas de. "Detecção de vazamentos em tubulações atraves da analise espectral de transientes de pressão." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267583.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Uma nova técnica de detecção de vazamentos em tubulação é apresentada. A técnica é baseada na análise espectral de sinais de pressão medidos em trechos da tubulação que favorecem a formação de ondas estacionárias. Sendo baseada no espectro do sinal, e não na sua representação temporal, a análise possibilita a identificação do vazamento mesmo quando este ocorre durante a realização de operações que naturalmente encobririam o transiente de pressão gerado pelo vazamento. Testes experimentais foram realizados numa tubulação de 1250 m de comprimento em várias condições de fluxo e configurações de vazamento durante a partida e a parada de uma bomba centrífuga. Transientes de pressão foram obtidos por quatro transdutores conectados a um computador padrão PC comandado por um software de aquisição de dados e controle desenvolvido. Os testes mostraram que a análise espectral dos transientes de pressão, juntamente com o conhecimento dos pontos de reflexão na tubulação, consiste em um método simples e eficiente de se detectar vazamentos
Abstract: The development and test of a technique for leak detection in pipelines is presented. The technique is based on the spectral analysis of pressure signals measured in pipeline sections where the formation of stationary waves is favoured, allowing leakage detection during the start stop of pumps. Experimental tests were performed in a 1250 m long pipeline for various operational conditions of the pipeline (liquid flow rate and leakage configuration). Pressure transients were obtained by four transducers connected to a PC compute. The obtained results show that the spectral analysis of pressure transients, together with the knowledge of reflection points provide a simple and efficient way of identifying leaks during the start stop of pumps in pipelines
Doutorado
Sistemas de Processos Quimicos e Informatica
Doutor em Engenharia Química
Franco, Cañellas Antoni Verfasser], and Frank [Akademischer Betreuer] [Schreiber. "Impact of partial nitrogen and fluorine substitution on the interface properties of π-conjugated molecules adsorbed on inorganic substrates. A combined photoelectron-spectroscopy and X-ray-standing-waves study / Antoni Franco Cañellas ; Betreuer: Frank Schreiber." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1209540436/34.
Full textBen, Jabrallah Soumaya. "Electrolytes aux interfaces : accès aux premiers nanomètres par la technique des ondes stationnaires." Electronic Thesis or Diss., Paris 6, 2016. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2016PA066709.pdf.
Full textThe distribution of ions and charges at solid-water interfaces is of key importance in a number of phenomena and processes. In particular the development of microfluidics has strengthened the need for understanding and controlling ion distributions in the electric double layer. Indeed, phenomena occurring within the diffuse Gouy-Chapman layer become dominant in determining flow properties as channel size become on the same order of magnitude of the Debye length. In this thesis, we used the technique of X-ray standing waves to determine the distribution of interfacial ions. We have developed cells with thicknesses of a few hundred nanometers or less, precisely measured by X-ray reflectivity. The liquid film is confined between the multilayer which create the standing wave and a polymer film. The ion fluorescence allows to determine the interfacial distribution with a spatial resolution of a few Angstroms. This work was carried out for solutions containing different mixtures of monovalent ions (chloride, potassium, cesium and iodine) at several concentrations.In the second part of this work, we present the results for lanthanide chlorides. These studies have allowed us to determine the composition of the Stern layer and the distribution of ions in this layer for all pairs La3+/Ce3+, La3+/Eu3+, La3+/Gd3+, Ce3+/Eu3+, Ce3+/Gd3+ et Eu3+/Gd3+. We could then classify these ions and discuss the series
Petculescu, Gabriela. "Fundamental Measurements in Standing-Wave and Traveling-Wave Thermoacoustics." Ohio University / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1020690543.
Full textPerfetti, Claire. "Particle manipulation in minichannels for enhanced digital holographic microscopy observation." Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209283.
Full textsizes - mostly in the nano to millimeter scale - when dispersed in a carrier medium, is an increasingly important topic in many fields such as biotechnology,nanotechnology, medicine, biophysics and environmental monitoring and remediation. The underlying rationale for using such techniques stands in the sometimes compelling requirements of avoiding clogging as in micro/nano channel flows, of limiting sedimentation and wall interactions in particle/cell counting, of enhancing particle-surface interaction as in bio-sensing or of facilitating characterization and sorting as in bio-physical applications. Being developed in the frame of a Belgian national project devoted to the characterization and counting of pollutant in water media by digital holographic microscopy, this thesis tackles a peculiar class of particle manipulation techniques, commonly known as Focusing. The main goal of focusing is to avoid at best wall particle interactions and sedimentation, prevalent issues for dispersions owing in micro/mini-channels especially for applications such as optical characterization and counting.
The main attention was given to two flow focusing techniques - Hydrodynamic and Acoustic Focusing - for their wide range applicability and cost effectiveness. Hydrodynamic Focusing consists in controlling the position and spreading of the sample under investigation by means of a so-called sheath flow. A low-cost, nevertheless effective, prototype has been conceived, designed, manufactured and tested. It allowed for controlling the spreading of the sample stream and achieving a focusing ratio accounting for only 4% of the original stream width.
Acoustic Focusing takes advantage of the time-averaged pressure fields induced by the creation of standing waves in channels to manipulate and focus the dispersed particles. In the frame of this thesis, several devices have been developed using square cross section glass mini-channels. Aside from the cost-effectiveness, particles where focused in a somehow unexpected but high reproducible 3D matrix-like structure. A novel numerical model has also been implemented in order to study the conditions leading to the 3D structure formation. A good agreement between experimental and numerical results was found./Ce projet de thèse portant sur la manipulation de micro-particules dans des minicanaux s'inscrit dans le développement de cellules de flux pour des applications biologiques, qui est l'une des problématiques du projet HOLOFLOW, soutenu par
la région de Bruxelles Capitale. Les cellules de flux doivent permettre l'observation et la reconnaissance des micro-organismes vivants dans une large gamme de dimensions (de quelques microns à 1mm) avec la microscopie holographie digitale.
La problématique d'observation et de manipulation des microorganismes en flux est liée au clogging (bouchage) et à la sédimentation qui limitent la durée de vie des cellules d'observation. Ce projet de thèse s'inscrit dans cette problématique et propose deux axes d'étude pour limiter l'interaction entre organismes et canaux, la focalisation hydrodynamique, basée sur le guidage de flux, et la focalisation acoustique, basée sur la manipulation des particules.
La focalisation hydrodynamique est une technique basée sur l'injection différentiée de l'échantillon à observer et d'un fluide support. La différence des vitesses d'injection des flux permet de contrôler la dispersion des particules afin d'optimiser leur observation. Dans le cadre de cette thèse, un prototype à bas-coût a été développé et construit, permettant de focaliser les particules dans un faisceau jusqu'à 4% de leur faisceau incident.
La focalisation acoustique utilise la création d'une onde acoustique stationnaire afin de regrouper les particules en suspension au centre du canal. Au cours de cette thèse, plusieurs prototypes ont été réalisés, mettant en évidence la formation de motifs tridimensionnaux. Un model numérique a été spécialement développé afin d'étudier les conditions de génération de ces motifs, et de nombreuses expériences ont été menées afin de s'assurer de leur reproductibilité. Une bonne adéquation entre la position des particules mesurée et calculée numériquement a été démontrée.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Pešek, Marko. "Modulární systém pro měření charakteristik dvoupásmových reproduktorových soustav." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-401980.
Full textManneberg, Otto. "Multidimensional Ultrasonic Standing Wave Manipulation in Microfluidic Chips." Doctoral thesis, KTH, Biomedicinsk fysik och röntgenfysik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10919.
Full textQC 20100730
Miranda, Caio Marcelo de. "Determinação da frequência de autorressonância por onda estacionária em enrolamentos solenoidais e proposta de um sistema autorresonante de transferência de energia sem fio utilizando bobinas bifilares abertas." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2742.
Full textComuns em projetos de engenharia elétrica, bobinas solenoidais com núcleo de ar e camada simples de enrolamento podem apresentar frequência de autorressonância por efeitos de onda estacionária. A compreensão e determinação destas frequências é portanto de primordial interesse para os profissionais envolvidos com estes componentes. Neste trabalho é apresentada uma teoria que visa explicar o comportamento deste componentes quando em autorressonância por onda estacionária, sendo também desenvolvida uma equação prática que pode determinar tais valores de frequência. O comportamento da impedância nestes componentes também é discutido e demonstrado, onde, baseado nesta teoria, duas novas configurações são apresentadas: uma bobina com ambos terminais abertos e uma bobina com ambos terminais aterrados. Através de uma abordagem didática, correlaciona-se o enrolamento com um tubo de ar ressonante, e explica-se o que é registrado em termos de impedância e fase em um analisador vetorial de impedâncias ao conectar em seus terminais um enrolamento que apresenta autorressonância por onda estacionária. Uma análise da transferência de energia sem fio em circuitos ressonantes magneticamente acoplados é também apresentada, onde é destacada a relação entre eficiência, transferência relativa de potência e impedância refletida em circuitos com 2 e 4 bobinas. Um sistema de transferência de energia sem fio, utilizando bobinas bifilares abertas, é proposto. O sistema possui algumas vantagens uma vez que, a bobina bifilar aberta, ao contrário de uma bobina convencional, possui uma autorressonância série. Portanto, o sistema se comporta como um circuito contendo indutor e capacitor em série. Ainda, uma vez que o circuito dispensa o uso de capacitores, possibilita-se uma menor dimensão das unidades transmissora e receptora, além de se evitar eventuais danos aos capacitores em aplicações envolvendo maiores potências.
Common in electrical engineering projects, air-core single-layer solenoid coils can present self-resonant frequencies due to stationary waves effects. The comprehension and determination of these frequencies is of primordial interest for the professionals evolved with these components. In this work, a theory that aims to explain these components behavior at standing wave self-resonance is presented, a practical equation that can determine such frequency values is also developed. The impedance behavior in these components is also discussed and demonstrated, where, based in this theory, two new configurations are presented: a coil with both terminals open and a coil with both terminals grounded. Through a didactic approach the coil and a resonant air-pipe are correlated, and it is explained what is registered in terms of impedance and phase on a vector impedance analyzer when a standing wave self-resonant coil is connected on its terminals. An analysis of the wireless energy transfer in magnetically coupled resonant circuits is also presented, being emphasized the relation between efficiency, relative power transfer and reflected impedance in 2 and 4-coils circuits. A wireless power transfer system using open bifilar coils is proposed. The proposed system has the advantages that the open bifilar coil, different from a conventional coil, has a series self-resonance. Thus, the system behaves as a series-inductor capacitor circuit. Also, since the circuit avoids capacitors, it allows a smaller transmitter and receptor units dimensions, besides avoiding eventual damages to capacitors in higher power applications.
Desmau, Morgane. "Rôle des biofilms bactériens sur le devenir des nanoparticules manufacturées dans les sols." Thesis, Sorbonne Paris Cité, 2018. https://theses.md.univ-paris-diderot.fr/Desmau_Morgane_complete_20181219.pdf.
Full textOver the last decades, the important increase in nanoparticles (NPs) production and use resulted in their release in the environment and raise important concerns regarding their potential to negatively impact ecosystems. In the environment, NPs are likely accumulated in soil where it is expected that they will interact with bacterial biofilm/mineral interfaces, one of the most reactive compartment. This complex interface exhibits highly specific physico-chemical properties that can control NPs fate and transformations (dissolution, aggregation…). During this PhD work, I was interested by the partitioning of NPs at this interface, the transformations that NPs can undergo and to physico-chemical parameters that control NPs behavior. To do so, Shewanella oneidensis MR-1 biofilms were grown on oriented single crystals -Al2O3 (1-102) and were exposed to silver nanoparticles and Quantum Dots. NPs partitioning and stability were mostly investigated using Long Period – X-ray Standing Waves – Fluorescence Yield spectroscopy and Grazing Incidence – X-ray Absorption Spectroscopy. This work allows to demonstrate that NPs partitioning at the interface is mostly controlled by the mineral surface. Nevertheless, biofilm is able to slow down NPs migration depending on NPs size and aggregation state, NPs surface charge and coating type ((in)organic, hydrophobic properties). When NPs migrate through biofilm thickness, they undergo transformation, and more specifically dissolution. This dissolution is partly controlled by microenvironments within biofilm thickness but also by the presence of thiol groups at EPS and cells surfaces as well as in molecules secreted by bacteria
Schumacher, Erik. "Diffraction of atoms by a standing-wave light field." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185757.
Full textPérez, Pastor Antonio María. "Análisis del efecto multipactor en guías de onda de geometría cilíndrica." Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/162975.
Full text[CA] El propòsit de la present tesi és desenvolupar una eina informàtica per a la predicció de l'efecte multipactor tant en línies de transmissió coaxials com en guies circulars. Aquesta eina està pensada per a ser complementària de les de disseny assistit per ordinador Computer- Aided Design (CAD) en el cas de dispositius de comunicacions a implementar en aquestes tecnologies d'ones guiades. En el cas de guies coaxials, es desenvoluparà un model numèric per a la predicció dels llindars de potència del fenomen de multipactor. Aquest mètode ha sigut validat amb mesures experimentals, així com validat amb altres estudis teòrics realitzats. En aquesta mena de guia s'ha considerat tres tipus de senyal de ràdio freqüència (RF), l'ona incident, l'ona estacionària pura i les ones estacionàries en general (combinació d'ones incident i reflectida de diferents amplituds). Així doncs, s'ha analitzat i obtingut els llindars de potència per a cadascuna dels diferents senyals considerats i observat els efectes que es produeixen. En les guies circulars, s'ha demostrat en primer lloc l'existència del fenomen de multipactor sota l'excitació de la manera fonamental de la guia circular TE11. L'interés en aquestes guies es deu a l'ampli ús en la fabricació de components passius, tant en cavitats ressonants com l'ús d'irises que connecten les cavitats, emprats tant en acceleradors de partícules com en diferents subsistemes de comunicacions en satèllits. Per tant, a més d'observar l'existència de l'efecte multipactor hem calculat una carta de susceptibilitat per a aquest fenomen, inicialment en el cas que només es transmeta una única polarització, en concret la polarització vertical. Una vegada hem demostrat que l'efecte multipactor és possible en aquestes guies circulars, s'ha realitzat un estudi tenint en consideració la coexistència de les dues polaritzacions de la manera fonamental TE11. Per a una millor comprensió del fenomen, s'ha analitzat inicialment per a ordres de multipactor més baixos en funció de l'excentricitat de l'ellipse de polarització. Prestant especial atenció per al cas de la polarització lineal i circular, encara que també s'ha analitzat altres combinacions més generals.
[EN] The main goal of this PhD thesis is to develop a computer tool for the prediction of the multipactor effect, both in coaxial transmission lines and in circular guides. This tool is intended to be complementary to the available Computer-Aided Design (CAD) versions, in particular for the case of communication devices to be implemented in the cited guided wave technologies. In the case of coaxial guides, a numerical model is developed to predict the power thresholds of the multipactor phenomenon. This method has been validated with experimental measurements, as well as with other theoretical studies carried out. In this type of guide, three types of radio frequency (RF) signals have been considered, i.e. the incident wave, the pure standing wave and the standing waves in general (a combination of incident and reflected waves of different amplitudes). Thus, the power thresholds for each of the different signals considered have been analyzed and obtained, and the corresponding effects that occur have been observed. In circular guides, the existence of the multipactor phenomenon under the excitation of the TE11 fundamental mode of the circular guide has been demonstrated first. The interest in these guides is due to their wide use in the manufacture of passive components, both in resonant cavities and within irises that connect the cavities, used both in particle accelerators and in different satellite communications subsystems. Therefore, in addition to observing the existence of the multipactor effect, we have calculated a susceptibility chart for this phenomenon, initially in the case that only a single polarization is transmitted, specifically the vertical polarization. Once we have shown that the multipactor effect is possible in these circular guides, a study has been carried out taking into account the co-existence of the two polarizations of the TE11 fundamental mode. For a better understanding of the phenomenon, it has been initially analyzed for lower multipactor orders as a function of the eccentricity of the polarization ellipse. Special attention has been paid to the case of linear and circular polarization, although other more general combinations have also been analyzed.
This work was supported in part by Ministerio de Educación y Ciencia, Spanish Government, under the coordinated Research Project TEC 2007/67630-C03-01 and in part by Generalitat Valenciana (Spain) under Projects IIARC0/2004/20, IIARC0/2004/21 and IIARC0/2004/22. This work has been supported by Ministerio de Ciencia e Innovación, Spanish Government, under Research Project TEC2007-67630-C03-01.
Pérez Pastor, AM. (2021). Análisis del efecto multipactor en guías de onda de geometría cilíndrica [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/162975
TESIS
Scragg, Glyn Frank. "X-ray standing wave studies of adsorbates on metal surfaces." Thesis, University of Warwick, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319816.
Full textChenkosol, Pitak. "Spontaneous coherent pulsations in standing-wave laser oscillators : stability criteria." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4211.
Full textAnjos, Hudson Umbelino dos. "Soluções para uma Classe de Equações de Schrödinger Quase Lineares via Método de Nehari." Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/7460.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
In this dissertation, we study existence of both one-sign and nodal positive solutions (with exactly two nodal domains) for a class of quasilinear Schrödinger equations, which model physic phenomena, for example, in plasma physics. To obtain the results, it was used, mainly, the Nehari method, as well as, regularity theory of elliptic and Concentration-Compactness Principle.
Nesta dissertação, estudamos a existência de soluções positivas e mudando de sinal (tendo exatamente dois domínios nodais) para uma classe de equações de Schrödinger quase lineares, as quais modelam fenômenos físicos, por exemplo, em Física dos Plasmas. Na obtenção dos resultados, foi usado, principalmente, o método de Nehari, bem como teoria de regularidade elíptica e o Princípio de Concentração-Compacidade de P. L. Lions.
Halpin, Gabriel M. "Enhancing GaN LED Efficiency through Nano-Gratings and Standing Wave Analysis." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1120.
Full textLee, John Jethro. "Photoemission-monitored x-ray standing wave studies of molecular adsorbate surface structure." Thesis, University of Warwick, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272660.
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